Chapter 10 Flashcards
What is transcranial doppler?
A noninvasive test that uses ultrasound to measure the velocity of blood flow through the intracranial cerebral vessels
What is transcranial duplex imaging?
A noninvasive test on the intracranial cerebral blood vessels that uses ultrasound and provides both an image of the blood vessels and a graphic display of the velocities within the vessels
What is the circle of willis?
A roughly circular anastomosis of arteries located at the base of the brain
What is a vasospasm?
A sudden constriction in a blood vessel, causing a restriction in blood flow
What is a collateral?
A vessel that parallels another vessel; a vessel that is important to maintain blood flow around another stenotic or occluded vessel
What arteries are part of the anterior circulation?
Cavernous internal carotid artery, ICA branches, Middle cerebral artery, Anterior cerebral artery, and Anterior communicating artery
What arteries are part of the posterior circulation?
Vertebral arteries, Basilar arteries, and Posterior cerebral arteries
What measurement is TAP-V?
mean velocities
What vessels have low resistance flow?
All except OA
What type of resistance is found in the opthalmic artery?
High resistance
What are the 4 acoustic windows used to access cerebral vasculature?
Transtemporal, transoccipital, transorbital, and submandibular
What should you do to the power intensity when doing a transorbital approach?
lower it
What is another name for the transoccipital approach?
Foramen Magnum
Using the foramen magnum apprach how should the transducer be placed?
At the base of the skull and aimed toward the nose
What arteries are identified during the transorbital apprach?
OA and cavernous carotid
What arteries are identified during the transtemporal approach?
MCA, Anterior cerebral artery, TICA, and Posterior cerebral artery
When can you see the PCOA and the ACOA while using the transtemporal approach?
If they are working as collaterals
When using trans temporal approach what should you do with the power?
Increase it
When using the foramen magnum approach what arteries are identified?
Vertebral arteries and Basilar arteries
What is considered normal direction of flow when using the transoccipital approach?
Away from the transducer
